Raspberry (Rubus idaeus L.) waste-derived nanocellulose for circular application in edible films and coatings

Due to the overuse of petroleum-derived polymers and the consumer demand for nutritious and healthy products that can maintain their quality over longer periods of time, there is a need for new sustainable packaging systems that fulfill these requirements. Lignocellulosic biomass, particularly agricultural pruning residues, offer great potential for obtaining biopolymers through biorefining processes. In this study, raspberry pruning residues were used to produce lignocellulose nanofibers (LCNF) and cellulose nanofibers (CNF), by varying the intensity of TEMPO-mediated oxidation pretreatment (5 and 10 mmol/g) and examining the amount of residual lignin and its impact on reinforcement capacity in food edible films and coating using chitosan-based formulations. The addition of CNF/LCNF up to 0.05 g/g of film, improved the mechanical properties of films, with Tensile Strength (TS) reaching a highest value of 40.98 MPa for 0.03 g/g LCNF-TO5 films. The presence of residual lignin in LCNF enhanced the optical properties of the films, particularly in terms of UV light blocking, with values of 84.56% achieved for 0.15 g/g LCNF-TO5 samples. The use of a coating with concentrations of up to 0.1 g/g LCNF resulted in improved firmness values and lower counts of aerobic mesophilic bacteria (AMB) after 7 days of storage.

Automated summary

Due to the overuse of petroleum-derived polymers and the consumer demand for nutritious and healthy products that can maintain their quality over longer periods of time, there is a need for new sustainable packaging systems. In this study, lignocellulosic biomass derived from raspberry pruning residues was used to produce biopolymers. The addition of nanofibers improved the mechanical properties and optical properties of the films, and the coating with nanofibers resulted in improved firmness values and lower counts of bacteria after storage.